I'm no mountain bike expert but I wouldn't be so quick to write this one off as a Walmart level bike. Mid-90s dual suspension bikes had similar design and rear suspension setups. Gary Fisher Joshua comes to mind.

Tough picture, but OPs bike looks to have a couple of details like a rear derailleur hanger and quick release hubs that differentiate it from the Walmart bike. That said, the fork looks a little low end but again, I'm no expert. I'd investigate further before dismissing as low end bike.